<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>React router 4</title>
    <link href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet">
    <link href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap-theme.min.css" rel="stylesheet">

    <style>
        .active{
            color:red
        }
    </style>
</head>
<body>
<div id="app"></div>
<script src="bundle.js"></script>
<script src="https://cdn.bootcss.com/jquery/2.2.3/jquery.js"></script>
<script src="https://cdn.bootcss.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>

</body>
</html>